Many types of machines use fluid power for their operation. Compressed air is a common type of fluid power which may be used to operate pneumatic cylinders, air motors and a wide variety of other devices.
It is common to use hoses to connect pneumatic devices to a source of compressed air. For ease of connection, it is also common to use a quick connect/disconnect coupling to connect the hose to the compressed air supply. In most applications, a male fitting is positioned at the end of the hose and a female fitting is in communication with the source of supply. This insures that the hose is open to atmosphere when it is disconnected from the female fitting. In addition, valves are commonly built into the female portion of the coupling so that the flow of compressed air is shut off as soon as the male fitting is removed.
It is sometimes necessary to shut down equipment that is powered by compressed air. Reasons for shutting down the equipment include the necessity of making repairs which cannot be made while the equipment is running. Inadvertent starting of the equipment while it is being worked on could cause damage to the equipment or injury to the persons attempting to repair it.
When pneumatic equipment is turned off for repair, it is desirable to disconnect the equipment completely from the source of compressed air. This insures that the pneumatic components are deactivated. When the equipment is connected with the hose having a quick connect/disconnect coupling, the easiest way to disconnect the equipment from the supply of compressed air is to disconnect the hose.
There is always a possibility that someone who is not aware that the equipment is being worked on may see the disconnected hose and reconnect it to the compressed air supply. This would most likely happen in multi-shift operations where the persons who started the repair process have gone home without informing the individuals working on subsequent shifts. Of course, stickers or tags may be used to indicate that the hose fitting should not be reconnected. However, such items may fall off the hose and can be rendered illegible in a dirty environment.
Thus, there exists a need for a lockout device for a hose fitting that prevents a pneumatic hose from being connected to a compressed air supply when the equipment supplied by the hose is being repaired.